WASHINGTON — Two top executives at failed MF Global plan to tell a Senate committee Tuesday they do not know where customer money missing from the collapsed firm is located.

As much as $1.2 billion in client funds may be unaccounted for after the eighth-largest bankruptcy in US history. That’s according to a trustee overseeing distribution of customer money for the firm.

“I do not know why these funds cannot be accounted for, but based on the fact that no shortfalls had been reported to me previously, it appears that any irregularities were likely caused by events that occurred shortly before the bankruptcy filing,” said MF Global Chief Financial Officer Henri Steenkamp in testimony obtained by MarketWatch.

Steenkamp is scheduled to testify at a hearing Tuesday in the Senate Agriculture Committee about the MF Global failure.

Steenkamp’s comments match those made by Jon Corzine, the former chief of MF Global. Corzine testified before a House Agriculture committee Thursday. Corzine was subpoenaed for the hearing and is scheduled to testify with Steenkamp.

Bradley Abelow, president and chief operating officer of MF Global, is also set to tell lawmakers Tuesday that he doesn’t know where the funds are located. Both Abelow and Steenkamp agreed to testify voluntarily, according to a spokeswoman for the Republican staff of the committee.

“I am deeply troubled by the fact that customer funds are missing, and I can assure you that I share your interest, and the public’s interest, in finding out exactly what happened,” Abelow said in testimony prepared for the hearing Tuesday obtained by MarketWatch. “At this time, however, I do not know the answers to those questions.”

New York-based MF Global filed for bankruptcy protection on Oct. 31 after disclosing sizable exposure to derivatives and other investments related to billions of dollars in European sovereign debt.

Regulators are investigating whether the firm tapped into customer segregated futures accounts for its own proprietary trading. No one at the firm has been charged so far.

The Commodity Futures Trading Commission, Securities and Exchange Commission and the FBI are conducting investigations into the failure.